A flat panel display has recently been developed to be used in place of a conventional CRT display. The flat panel displays include LCD (liquid crystal display), PDP (plasma display panel) and EL (electroluminescence display). The liquid crystal display has already been used in practice. Further, the development of the plasma display panel has reached a practical stage. The flat panel display as well as the CRT display has a problem of reflection of light, which degrades the visibility of the display.
An anti-reflection film has been proposed to solve the problem of reflection of light. For example, Japanese Patent Provisional Publication No. 59(1984)-50401 discloses an anti-reflection film having a double layered structure shown in FIG. 2 and an anti-reflection film having a triple layered structure shown in FIG. 1.
The anti-reflection film shown in FIG. 1 comprises a transparent support (11, base), a high refractive index layer (12, first layer) and a low refractive index layer (13, second layer) in the order. According to the invention of Japanese Patent Provisional Publication No. 59(1984)-50401, the refractive index (n.sub.1) and the thickness (d.sub.1) of the high refractive index layer as well as the refractive index (n.sub.2) and the thickness (d.sub.2) of the low refractive index layer satisfy the following formulas: ##EQU1## in which m is a positive integer, n is a positive odd number, and .lambda. is a standard wavelength (nm) selected from the visible region.
The anti-reflection film shown in FIG. 2 comprises a transparent support (21, base), a middle refractive index layer (22, first layer), a high refractive index layer (23, second layer) and a low refractive index layer (24, third layer) in the order. According to the invention of Japanese Patent Provisional Publication No. 59(1984)-50401, the refractive index (n.sub.1) and the thickness (d.sub.1) of the middle refractive index layer, the refractive index (n.sub.2) and the thickness (d.sub.2) of the high refractive index layer as well as the refractive index (n.sub.3) and the thickness (d.sub.3) of the low refractive index layer satisfy the following formulas: ##EQU2## in which 1 is a positive integer, m is a positive integer, n is a positive odd number, and .lambda. is a standard wavelength (nm) selected from the visible region.